Enhancing Near‐Room‐Temperature Thermoelectric Performance of n‐Type Mg3(Bi,Sb)2‐Based Materials through Induction Sintering and Mg Evaporation Control

Abstract n‐type Mg 3 (Bi,Sb) 2 is a newly developed high‐performance thermoelectric material with significant potential for use in next‐generation thermoelectric coolers (TECs) at room temperature. However, its electrical transport properties, sensitive to magnesium content and high vapor pressure, pose challenges for manufacturing. Herein, using the finite element method, it is demonstrated that reducing the effective specific surface area suppresses magnesium evaporation. Increasing the thickness of the Mg 3 (Bi,Sb) 2 pellet ( φ = 12.7 mm) from 3 to 10 mm reduces evaporation by approximately 60%. Building on this, an induction sintering technique is employed, which extends sintering time at 1053 K, enabling the successful preparation of n‐type 0.25%‐Te‐doped Mg 3 (Bi,Sb) 2 material. The as‐obtained Mg 3.2 Bi 1.4975 Sb 0.5 Te 0.0025 material exhibits a thermoelectric figure of merit (zT) value of approximately 0.83 at room temperature, attributed to a 20‐fold increase in Hall mobility to lattice thermal conductivity ratio. The homemade seven‐pair module of n‐type Mg 3 (Bi,Sb) 2 and commercial p‐type Bi 2 Te 3 achieves a maximum temperature difference of 63.4 K at room temperature, one of the highest reported. These results reaffirm the superior performance of n‐type Mg 3 (Bi,Sb) 2 and propose an economical approach to scalable production.